Heat capture, transfer and release for industrial applications

ABSTRACT

Embodiments of the invention provide systems and methods for heat transfer at temperatures in the range of −40° C. to 1,300° C. over long distances with minimal heat losses. The systems consist of advanced heat pipes configured such that they fit inside drilling holes or in horizontal distance over industrial plants, and effectively transfer heat requiring minimal water, CO2, or steam injection, and that operate without user intervention for many years.

This invention relates to the field of thermal energy capture, transfer,and release in applications, such as thermal treatment for enhanced oilrecovery (EOR), heating underground geological deposits, recovering heatfrom geothermal sources, and efficiently transferring heat in multipleindustrial applications. In particular, embodiments of the inventionrelate to systems and methods of capturing, transferring, and releasingthermal energy from intermittent sources (such as metallurgicaloperations), continuous sources at high temperature (such as chemicaland petro-chemical operations) and continuous sources at low temperature(such as waste heat sources). A key feature of the invention is theability to transfer heat over short or long distances with minimal heatand temperature losses. The invention also includes methods ofmanufacturing devices for the capture, transfer and release of heatenergy, and methods to install such devices in numerous industrialapplications.

BACKGROUND

In most industrial situations, heat capture involves the transfer ofsuch energy from hot gases, liquids, or solids into other media thateither conduct heat away via thermal conductivity, as is the case ofheat exchangers, phase-change involving evaporation or melting, as isthe case of quenching reactions, or by convection or radiation. However,in many industrial systems heat is mainly dissipated rather thancaptured by conduction, convection or radiation. For example, meltingand quenching operations, such as the quenching of hot metallurgicalcoke with water, seldom capture the radiation or the steam produced, sothe heat is dissipated but not captured. Most heat capture operations inindustry rely on the thermal conductivity of a metal or other materialthat encapsulates the heat producing medium. This metal or othermaterial subsequently transfers the heat away from its source.Therefore, a critical parameter in heat capture is the thermal barrierpresented by the encapsulating material. This thermal barrier is also acritical parameter in the eventual release of heat.

When the heat is captured, methods of thermal transfer over distancenormally rely on either insulated steam pipelines or the transfer ofheat via thermal fluids which may include oil-based fluids, such asDowTherm®, eutectic mixtures such as molten salts, molten metals such asNa, or Pb, or Sn (these may be appropriate for metallurgicalapplications), or molten alloys. Steam is usually preferred in mostindustrial applications because it provides a considerable amount ofheat upon condensation, it is often the low cost option and is easilypumped over some distance. However, heat losses in moving steam are alsoquite significant in spite of insulation, and so the distance over whichsteam can be economically transferred is necessarily limited. The sameis true of thermal fluids with the aggravating feature of the additionalweight and costs involved. In the case of molten salts, the entirepipeline would require replacement if the salt were allowed to “freeze”in place, a problem that has often occurred.

In addition to the above limitations and parameters, some industrialapplications present unique problems to the capture, transfer, andrelease of heat, and deserve further discussion.

Heat Transfer in Enhanced Oil Recovery

In conventional oil production, oil is recovered from oil bearing saltdomes by drilling. Since the typical oil formation is under pressure,initial production is facilitated by the flow of oil to the surfaceunder pressure. Over time, such natural flow decreases as the pressuredeclines, and production relies on enhanced oil recovery methods. Thesemethods may include pressurization by injecting CO₂, water flooding, orheating with steam. Steam injection has become popular, because (a) theincrease in temperature caused by the steam decreases the fluidviscosity of the oil, (b) the water that condenses underground alsodisplaces the oil while increasing underground pressure, and (c) thedual phase flow may reduce overall flow viscosity.

As conventional oil deposits are exhausted, oil production isincreasingly relying on oil shales and similar formations that aregenerally less porous and more difficult to access. Such oil sources aregenerally subjected to hydraulic fracturing, otherwise known as“fracking,” where water pulses at great pressure are used to fractureunderground rocks so as to enhance porosity, thus allowing the flow ofhydrocarbons (natural gas or oil) to the surface. Over time, a similardecrease in the flow of hydrocarbons occurs as underground pressuredeclines with production, and similar EOR methods are employed: water,CO₂, or steam injection. All such methods are energy intensive andcostly. There is a need for EOR methods that are energy efficient andthat do not require vast amounts of water for either injection or steamproduction.

Heat Transfer from Geothermal Fields

Unlike the case of enhanced oil recovery where the problem is to getheat down to the oil below the surface, geothermal fields have thermalenergy already below the surface, and therefore heat can flow from thebottom to the top of a heat pipe or thermosyphon, while the workingfluid from the top to the bottom either by gravity, through a wick, orby both. Thus, the key impediment to the use of heat pipes in geothermalapplications is the distance of the heat transfer, that is, thepractical length needed for the heat pipe or thermosyphon.

Heat Transfer in Industrial Applications

Most industrial applications involve operating plants where facilitiesare distributed in a fairly level field sometimes covering several acresand numerous production units. Thermal energy in such facilities isnormally available where exothermic reactions take place, in boilerhouses, furnaces, and the like, whereas thermal energy may be requiredat some distance from those facilities. Thus, heat transfer atindustrial plants primarily involves horizontal transfer over hundredsor a few thousands of feet, but normally does not entail transfer over asignificant vertical distance.

Heat pipes, with their outstanding heat flux rates due to internal masstransfer of vapor, are well suited to horizontal heat transfer becausethere is no significant limitation of capillary action over distance.Thus, the main practical limitation for this type of application stemsfrom the length of commercially available heat pipes.

SUMMARY

Embodiments of the present invention provide novel means for capturing,transferring, and subsequently releasing heat that can be applied toindustrial applications, such as thermal treatment for enhanced oilrecovery (EOR), heating underground geological deposits, recovering heatfrom geothermal sources, controlling temperature in chemical processes,capturing and reusing waste heat in plants and factories, andefficiently transferring heat in a wide variety of other industrialapplications. In particular, embodiments of the invention relate tosystems and methods of capturing, transferring, and releasing thermalenergy from intermittent sources (such as metallurgical operations),from continuous sources at high temperature (such as chemical andpetro-chemical operations), and from continuous sources at lowtemperature (such as waste heat sources). A key feature of the inventionis the ability to transfer heat over short or long distances withminimal heat and temperature losses. The invention includes methods ofmanufacturing devices for the capture, transfer and release of heatenergy, and methods to install such devices in numerous industrialapplications. The invention allows for the rapid transfer of heat attemperatures in the range of −40° C. to 1300° C., or more, from avariety of heat sources, and the subsequent release of such heat atvariable or constant temperature for a long period of time. The systemincludes a novel heat pipe that is thermally insulated over most of itslength. In some embodiments, the low end of the temperature range can be0, 50, 100, 150, 200, and 250 degrees. The upper end of the temperaturerange can be 1500 or more, 1400, 1300, 1200, 1100, 1000, 900, 800, 700,600, 500, 400, and 300 degrees. In embodiments of the system, thedimensions of the heat pipe, the type of thermal insulation, thefabrication method, and its placement in the field are determined by theconditions and characteristics of each industrial application, by thedemand of heat transfer in terms of heat release, and by the type ofthermal energy available.

Some embodiments of the invention provide a heat management system thatcan include a plurality of heat transfer devices that can include, forexample, conventional heat pipes, advanced heat pipes, thermosyphons,heat spreaders, pulsating or loop heat pipes, steam pipes, and the like,assembled into an entity providing continuous thermal communication,adapted to capture, transfer, and release heat at temperatures in therange of −40° C. to 1,300° C. at a distances of from 0.1 m to 14 km,with a temperature loss from capture to release between 0% and 40% of atemperature at a source of the heat to be transferred, wherein the heatthus can be transferred from one or more heat sources, and wherein theheat transfer devices can capture or provide heat for at least oneapplication. In some embodiments of the invention, the distance can befrom 0.3 m, 1 m, 3 m, 10 m, 30 m, 100 m, 300 m, 500 m, and 1 km to 2 km,3 km, 4 km, 5 km, 6 km, 7 km, 8 km, 9 km, 10 km, 11 km, 12 km, 13 km, 14km, or more Likewise, in some embodiments of the invention, thetemperature loss or heat loss can be 0%, 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%,and 9% at a low end and 12%, 15%, 20%, 25%, 30%, 35%, or 40%, or more.Acceptable temperature loss can depend upon the circumstances of theparticular use of the system. In some situations, a very low heat lossis particularly advantageous and may be required in order for aparticular application to be cost-competitive. In other situations,where the competing technologies are ineffective or inoperable, a largeramount of heat loss or temperature loss can be acceptable and can behighly competitive with any alternative available. Accordingly, thedesired or market-required degree of minimization of heat loss can berelative to competitive alternatives.

In other embodiments, the heat management system can include one or moreheat transfer devices that can include, for example, conventional heatpipes, advanced heat pipes, thermosyphons, heat spreaders, pulsating orloop heat pipes, steam pipes, or the like, and can also include acombination of such heat transfer devices, assembled into an entity thatcan provide continuous thermal communication adapted to capture,transfer, and release heat at temperatures in the range of −40° C. to1,300° C. at a distance of from 500 m to 14 km with a temperature lossfrom capture to release between 0% and 40% of a temperature at a sourceof the heat to be transferred, wherein the heat thus can be transportedfrom one or more heat sources, and wherein the heat transfer devices cancapture or provide heat for at least one application.

In other embodiments, the heat transfer devices of the system can haveone or more wicks. In some embodiments, the heat transfer devices canhave no wicks. In some embodiments, the heat transfer devices caninclude an encapsulating material manufactured from, for example, steel,copper and its alloys, titanium and its alloys, aluminum and its alloys,nickel and chromium alloys, wound metal foils, wire screens, scaffolds,and the like, or any combination thereof. In other embodiments, the heattransfer device can include different metals and alloys that can includevarying thermal conductivities.

In other embodiments, the heat transfer devices of the system caninclude multiple sections such as, for example, evaporators, heattransfer sections, and condensers, or the like. In some embodiments, thesections can include a wick characteristic such as no wicks, full wicks,partial wicks, and the like, or any combination thereof.

In further embodiments, the application of the system can include, forexample, power plants, geothermal energy production, enhanced oilrecovery, gas recompression, water desalination, metallurgicalprocessing, chemical and petrochemical operations and production, pulpand paper industries, plastic and rubber operations, refractoryindustry, glassmaking operations, mining operations, plywood andoriented strand board manufacturing, fermentation, fertilizerproduction, industrial gas production, military applications, solarenergy production, rubber manufacturing, oil refineries, and the like.

In additional embodiments, the encapsulating material of the heattransfer devices can include, for example, a metal, plastic, or ceramiccomposition, or a composition combining such components, that can benon-reactive with respect to the variety of heat sources, non-reactivewith respect to a heat transfer medium, and non-reactive with respect tothe heat source.

In other embodiments, different individual wicked heat transfer devicescan be joined so a joined wick structure can exist, having continuitycompatible with capillary action along the length, the continuity canpermit thermal communication of internal working materials throughoutthe length, and the internal working materials include, for example,fluids, solids that sublimate, materials having multiple chemicalhydration levels, and the like, as well as any combination thereof.

In other embodiments, the wick structure can include multiple layershaving different porosities. In further embodiments, the wick structurecan include an internal wick structure that can include an axial wick.In other embodiments, the wick structure can include materials suchas,for example, sintered metals, metal screens, grooves, oxides,borates, solids that sublimate, materials with different chemicalhydration levels, nano-particles, nanopores, nanotubes, and the like.

In additional embodiments, different materials can be used at differentpositions along the length, and the materials can be selected tooptimize heat capture and release, while minimizing heat loss.

In other embodiments, the wick can be formed, for example, by spraying,painting, baking, PVD, CVD, pyrolysis of organic compounds, or the like.In some embodiments, the wick can be formed by thermally decomposing aslurry of metal particles in a liquid metal precursor and/or by similarprocesses.

In some embodiments, the encapsulating tube can include a wound strip offoil or the like; the foil can be thin in some embodiments.

In additional embodiments, the wound strip structure can be pre-coatedwith wick material before being formed into tubular assemblies around,for example, metal scaffolds or the like that can include, for example,mesh screens.

In some embodiments, any gaps in the wound tube can be sealed by aseparate wound strip or the like.

In some embodiments, the amount of working material can be in excess ofwhat is needed to saturate the internal wick structure.

In some embodiments, the working material in the heat transfer devicescan have a phase change temperature in the range of −40° C. and 1,300°C., or more.

In some embodiments, the heat transfer device can include at least onevalve proximate to at least one end in order to control and maintainpartial vacuum.

In some embodiments, vertical heat transfer devices of up to 14 km inlength can be installed in a manner to prevent the physical degradationor breakage of the heat transfer devices. In such embodiments, theweight of the heat transfer device is neutralized by, for example, atleast one buoyant balloon, at least one helicopter, a combinationthereof, or the like.

In various embodiments, the heat transfer devices can be installed usingat least one installation aid such as a crane, a helicopter, a balloon,a wheel, an oil rig, a tower, or the like. In some embodiments, heattransfer devices of, for example, 3-7 Km in length can be installedwithout physical degradation or breakage of such heat transfer devices,and the heat transfer device can be wound around a wheel of, forexample, 100-500 feet in diameter that minimizes the curvature of theheat transfer device. In some embodiments, the heat transfer devices canbe insulated.

In some embodiments, pulsating heat pipes can be made by encapsulating athin metal or alloy layer in, for example, a strong metal screen or thelike, to resist pressure pulses.

Some embodiments of the invention can include a method of heat capture,transfer and release using a heat management system.

Some embodiments include methods for manufacturing a heat managementsystem that can include the steps of: selecting the type of heattransfer device from, for example, conventional heat pipes, advancedheat pipes, thermosyphons, spreader heatpipes, loop heat pipes,pulsating heat pipes, steam pipes, any such combination, or the like;selecting a method of joining heat transfer device elements from, forexample, soldering, brazing, welding, threading, foil winding,mechanical fittings, encapsulating thermal fluids, any combination, orthe like; selecting a type of wick structure from, for example, sinteredmetal, axial wick, metal screens, grooves, any combination, or the like,or no wick material; selecting the internal working material from, forexample, aqueous solutions, eutectic salt mixtures, organic thermalfluids, or high-temperature metals and alloys that can liquefy attemperatures in the range of −40° C. to 1,300° C., solids thatsublimate, or materials with different chemical hydration levels; andadditionally the methods can include applying the joining method, wickstructure, and working fluid thus selected; and sealing the heattransfer device under vacuum.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 Shows a possible power plant configuration.

FIG. 2 Shows a ductwork configuration.

FIG. 3 shows aerodynamic shapes of heat pipes to minimize drag forces.

FIG. 4 Illustrates a ductwork configuration for minimal pressure drop.

FIG. 5 Shows an optional configuration for heat recovery from abaghouse.

FIG. 6 Shows an optional configuration for heat recovery from anelectrostatic precipitator (ESP).

FIG. 7 shows an optional heat capture configuration from intermittentheat sources.

FIG. 8 Shows a ductwork configuration for heat storage.

FIG. 9 Shows two optional configurations for recovering heat from theBayer Process.

FIG. 10 illustrates a cross sectional view of an embodiment of a heattransfer method for EOR.

FIG. 11 is a cross sectional view of an embodiment describing theinstallation of a heat transfer device for EOR.

FIG. 12 shows an alternative embodiment of an installation method ofheat transfer device for EOR.

FIG. 13 illustrates embodiments of heat transfer devices for geothermalinstallations.

FIG. 14 shows and alternative embodiment of a heat transfer device forindustrial plants.

FIG. 15 are diagrams of a heat transfer devices with a thermalinsulation.

FIG. 16 illustrates a cross sectional view of a heat pipe.

FIG. 17 is a schematic view of a high-performance heat pipe.

FIG. 18 illustrates two schematic diagrams of heat pipes.

FIG. 19 illustrates an alternative embodiment for long distance heattransfer.

FIG. 20 is a diagram of a method for making long heat pipes.

FIG. 21 is a cross sectional view of an alternative embodiment of awinding strip with a porous capillary surface.

FIG. 22 illustrates an alternative embodiment for making long heatpipes.

FIG. 23 illustrates an embodiment of an axial wick for heat pipes.

FIG. 24 illustrates an embodiment for maintaining internal vacuum inheat pipes.

FIG. 25 shows an alternative embodiment for making advanced heat pipes.

FIG. 26 shows an alternative embodiment for ultra-long advanced heatpipes.

FIG. 27 illustrates a heat pipe joining method.

FIG. 28 illustrates a method for interrupting heat transfer in a complexheat pipe.

FIG. 29 is a schematic of a heat transfer device.

DETAILED DESCRIPTION Definitions

Thermal energy or heat (in common usage) represents the thermal energyof molecules, atoms or ions including kinetic, vibrational androtational forms of energy. Heat also represents the transfer of kineticenergy from one medium or object to another, or from an energy source toa medium or object. Such energy transfer can occur in three ways:radiation, conduction, and convection but here will be used in a generalcommon sense to include available thermal energy content. Some believeheat refers to the transfer of energy between systems (or bodies), notto energy contained within the systems, but this understanding isunnecessarily restrictive. Others define heat as the form of energy thatflows between two samples of matter due to their difference intemperature, and that is also restrictive. The following definitions ofheat are useful:

-   -   a. A form of energy associated with the motion of atoms or        molecules and capable of being transmitted through solid and        fluid media by conduction, through fluid media by convection,        and through empty space by radiation.    -   b. The transfer of energy from one body to another as a result        of a difference in temperature or a change in phase.    -   c. Thermal energy either latent or sensible.

“Heat transfer devices” (HTDs), in the context of the current invention,include conventional and novel HP, spreader HP, thermosyphons, steampipes, and pulsating heat pipes. When heat pipes are mentioned as themethod of heat capture, transfer and release, pulsating heat and pipesspreader heat pipes can also be used. In vertical applications,thermosyphons can be used in place of heat pipes. Heat pipes are devicesthat can capture, transfer, and deliver heat more effectively than heatexchangers, metal surfaces, or thermal fluids because they operate ontwo physical principles and not just on thermal conductivity. Duringheat capture and release, heat pipes rely on both thermal conductivityand phase change, but the latter is several times more effective thanthe former, so the overall thermal performance is many times better thana comparable heat exchanger with similar surface area in theapplications under discussion. Furthermore, during heat transfer, theability of a heat pipe to transfer heat by mass transfer is, again, manytimes greater than the speed of thermal conductivity alone, even whendealing with highly conductive materials such as copper or silver. Thesuperior performance of heat pipes over thermal fluids in theapplications under discussion stems from the difference in specificheats of a common working fluid in heat pipe—water—versus the heatcapacity of organic liquids in the case of thermal fluids.

An important feature of HTDs described in the current invention is thesuperior heat transfer mechanisms of the heat pipes. As shown insubsequent paragraphs, heat pipes provide a means of transferring heatthat is near thermodynamically reversible, i.e., a system that transfersenthalpy with almost no losses in efficiency. Furthermore, whileconventional heat pipes share these unique mechanisms, the advanced heatpipes described herein are characterized by significantly improved heatcapture, transfer, and release performance and, thus, by approaching athermodynamically reversible process even closer.

There is a need for an inexpensive heat-transfer mechanism that canreadily transport heat at elevated temperature from surface operations,that can deliver such heat at constant temperature over a long period oftime to underground formations, that requires little or no maintenance,that is reliable, and that requires minimal water or steam foroperation.

Commercially available heat pipes come in lengths of a fraction of aninch to several feet, but not in hundreds or thousands of feet, andthere is a reason for that. As explained in sections of the detaileddescription, below, an essential aspect of a heat pipe is its ability tocirculate the condensed working fluid back to the hot area of the heatpipe. That ability is quite difficult to accomplish with currentmanufacturing processes, because a) capillarity forces in the current HPwould not be able to lift the liquid hundreds of feet and, b) anyinterruption in the internal capillary action would also interrupt theinternal transfer mechanism. Therefore, there is a need for long heatpipes that can be made to function effectively.

Heat Capture Using Heat Pipes, Spreader Heat Pipes, Thermosyphons, andPulsating Heat Pipes

FIG. 29 is a schematic of a heat transfer device, for example a type ofheat pipe. In FIG. 29 the heat pipe (4) is composed of three majorsections: a heat capture section (4′), a heat transfer section (4″), anda heat release section (4″). The heat transfer section is normallycalled the “adiabatic” section because heat losses are so small thatthey are normally ignored, so the term adiabatic is used, although heatlosses in adiabatic processes are never really zero.

Embodiments of the invention are disclosed herein, in some cases inexemplary form or by reference to one or more Figures. However, any suchdisclosure of a particular embodiment is exemplary only, and is notindicative of the full scope of the invention.

Industrial heat capture entails: (a) the capture of waste and/orlow-grade thermal (heat) energy, such as hot flue gases, (b) cooling ofvarious industrial and chemical processes, such as those that includeexothermic reactions, (c) controlling temperature in certain chemical orpetrochemical plants, such as controlling the oxidation of propyleneoxide at 200° C. during the production of propylene glycol, (d) usingheat capture for delivery at remote locations, such as in enhanced oilrecovery (EOR), and (e) capturing heat from difficult to accesslocations, such as tapping geothermal sources. Applicants review theseby means of examples that illustrate the broad scope of the invention invarious applications.

Capturing Waste, Low-, and High-Grade Thermal Energy

These industrial applications normally encompass large amounts of heatat temperatures that range from about 60° C. to perhaps as high as 250°C. which hinders the utilization of such energy for other heat consumingapplications, such as additional power generation. The industries thatgenerate large amounts of low-grade heat include but are not limited to(a) those that use large amounts of fuel and generate large amounts offlue gases, such as power plants, especially coal-fired plants,metallurgical and cement plants, and that dispose of those flue gases bymeans of stacks or chimneys (b) those that use industrial kilns,calcination furnaces, or process reactors, such as lime producers,alumina producers, magnesia producers, and many inorganic chemicalproducers (c) those that generate large amounts of heat without fluegases, such as nuclear power plants, compressors, power transformers,refractory plants, glassmaking plants, or thermal power plants withtheir large heat producing condensers.

Since fuel combustion constitutes a large fraction of energy generationfrom industry, capturing heat from flue gases becomes a relevantapplication for many industries. The recovery of heat from the flue gasof coal-fired power plants is selected to illustrate heat capturemethods and mechanism.

FIG. 1 illustrates a typical configuration for recovering heat from suchflue gases. In FIG. 1, the cross section of a typical flue gas duct (52)is a rectangular cross section measuring about 20×30 feet. A number ofheat pipes (4) penetrate the section of the flue gas (52). The heatpipes are in contact with the flue gas, which is at temperatures of 300°F. to 450° F., and capture a fraction of the available heat in the gas.Capturing only a fraction of the available heat is an important featurein this particular application, because the temperature of the fluegases cannot be allowed to drop excessively. Such a drop would impairthe eventual flow of flue gases through the disposal chimney. The heatpipes (4) that capture heat are connected to a larger and more complexheat pipe (58). This heat pipe has a larger diameter and, thus, greatercapacity for transferring large amounts of heat. Alternatively, one canuse different wick structures that are more efficient at long distances.The larger diameter heat pipe (58) transfers the captured heat toanother location where such heat is fed into a set of smaller diameterheat pipes (4) which in turn deliver such heat to a process vessel (53)that requires heat, such as, for example, the heat input section of awater purification system. Thus, an important function of heat captureinvolves using heat pipes that can transfer heat from the flue gases anddeliver it to other processes that are at a distance from the originalflue gas heat source.

FIG. 2 illustrates optional configurations for inserting heat capturedevices into ductwork. As shown in FIG. 2, the heat capture devices (4)(e.g., conventional heat pipes, thermosyphons, spread heat pipes, orpulsating heat pipes) are inserted part way into the cross section ofthe flue gas duct (52) either vertically as illustrated in FIG. 2(a) orhorizontally as shown in FIG. 2(b). In preferred configurations, heatpipes are placed co-linearly with the direction of flow of the fluegases so as to minimize the drag forces and, thus, the pressure drop inthe flue gas and potential erosion of the HP. Optionally, heat pipes canbe alternated between the vertical and horizontal direction, or atintermediate insertion angles. In addition, heat pipes can be placedadjacent or staggered to each other to minimize turbulence and pressuredrop and the thickness of boundary layers so as to maximize heattransfer from the bulk of the gas to the surface of the heat pipe.

FIG. 3 illustrates another feature of heat pipes that is useful forminimizing drag in fluid flow: the thermal performance of a heat pipe isindependent of the cross-sectional shape of the heat pipe, that is, thetransfer of heat is primarily dependent on the cross sectional area andthe surface area of the heat pipe, and far less on whether thecross-section is circular, rectangular, or another shape as long as thethickness of the gas boundary layer and residence times are similar.FIG. 3 shows a cross section of the flue gas duct (52) with a series ofheat pipes (4) with cross sectional shapes that aero-dynamicallydesigned to minimize drag, boundary layer thickness and maximum contacttime. Thus the leading heat pipe (4) has a different cross-section thanthe last heat pipe (4′) in the row.

FIG. 4 illustrates another method for minimizing drag in fluid flow. InFIG. 4, the heat pipes (4) are inserted at an angle with respect to thedirection of flue gas flow. Normally, drag forces and erosion areminimized when this angle is about 30° from the direction of flow,although other angles may be preferred depending on the configuration ofthe ductwork.

Typically in a coal fired power plant, the combustion gases are firstsubject to catalytic denitrification by means of ammonia or amines, thenash in the flue gases is reduced by either filtration in a baghouse orelectrostatic precipitation. Subsequently, the flue gases are conveyedby means of the flue duct into a fan that increases the pressure priorto flue-gas desulfurization (FGD). Following FGD, the flue gases arevented to the atmosphere by means of a stack or chimney, which isanother point of potential capture for low-grade heat. FIG. 5 shows analternative configuration for capturing heat directly from ductwork in acoal fired power plant, that is, capturing heat at the baghouse (66). InFIG. 5, the heat pipes (4) are placed inside (the clean side) thefilters of the baghouse (66) in order to minimize ash deposition ontothe heat pipes. The flows of the flue gas and the flows of the fluidinside the heat pipes will be parallel and concurrent. The hot gas willcontact the heat pipe and heat captured at the bottom of the heat pipe,will be rapidly transferred outside the baghouse area. which willinitiate cooling of the flue gas. The total pressure drop of the flow inthe filter bag will be proportional to the inverse of the freecross-sectional area inside the bag. For a 1 cm diameter heat pipeinside a 10 cm diameter ceramic filter, the additional pressure drop dueto the heat pipe will be: 10²/(10²−1²)−1 or approximately a 1% extrapressure drop. If one places 6 heat pipes, one still has10²/(10²−6×1²)−1 or approximately a 6% increase in pressure drop, whichis within the margins of fluctuation of the flue gas system. The number,distribution and diameter of heat pipes will be determined by thedimensions of the filter bags and the desired fraction of heat to berecovered.

FIG. 6 shows still another optional configuration for capturing heatdirectly from ductwork in a coal-fired power plant, that is, capturingheat at the electrostatic precipitator (67). The electrostaticprecipitator system is designed to have maximum area of contact with theflue gas to be able to charge most of the particles flowing by with aminimum pressure drop. Therefore, the contact gas-solid contact isalready good. A preferred configuration is to make the perforated plates(see FIG. 6) to be heat pipes. The plates already have connection to theexternal electrical powering system, so the across the roof connectionscould also be used as heat transfer conduits, the HP themselves. FIG. 6illustrates the proposed configuration in an electrostatic precipitator.Since no changes in the flue gas flow are considered, the pressure dropin this particular configuration would be that of the electrostaticprecipitator without any further increase.

The benefits of these last two configurations—capturing heat at thebaghouse or at the electrostatic precipitator—are twofold: first heat iscaptured at a slightly higher temperature than in the flue-gas duct thusimproving thermal efficiency, and second each of these process units canbe used to perform dual functions, their original function and theadditional heat capture function. Note also that since with the use ofHP, the electrostatic precipitator will be kept at a lower temperaturethan in the conventional mode and as consequence it will attract moreand even finer particles driven by thermo-foretic forces thus furtherenhancing the filtering action.

Industrial operations that generate large amounts of heat intermittentlyconstitute a special case. Those operations occur in such industries asintegrated steel plants that utilize oxygen converters, secondary steelplants that use electric furnaces, and non-ferrous plants that producemetals like copper, lead, silicon, or titanium. The processes in theseplants all generate large amounts of heat at very high temperatures butnot necessarily continuously. The capture of this type of intermittentlyproduced heat is similar to previous examples described above, but thetransfer and release of such heat presents restrictions that are notfound in continuous heat sources. One option is to capture heat for usein applications that also operate intermittently. Another is to storethe intermittent heat in a separate vessel filled with a thermal fluid:DowTherm® or equivalent for medium to low temperatures, molten salts oreutectics for higher temperatures, or advanced heat storage systems,such as “Heat Transfer Interphase,” filed 12 Jan. 2011, with prioritydate of 12 Jan. 2010, and with the International Application Number ofPCT/US2011/021007, and assigned to Sylvan Source, Inc, which isincorporated by reference in its entirety.

Thus, it is clear that there is a dual industrial need: (a) the need fornovel heat pipes that capture, transfer, and release thermal energy overlong distances, including vertical distance, and (b) the need forstoring thermal energy from high-temperature sources that areintermittent. The combination of such dual features opens up multipleindustrial applications that are not possible otherwise.

FIG. 7 illustrates heat capture from an oxygen converter, which isnormally used in integrated steel plants, as well as in copper and leadplants. In FIG. 7, an oxygen steel converter (71) contains molten iron(72) saturated with carbon and covered by a thin layer of slag (73).Oxygen gas is blown into the molten iron by means of an oxygen lance((74) for periods on the order of 20 to 30 minutes and, during thisoperation, copious amounts of combustion gases (75) containing CO andCO₂ evolve at very high temperature, higher than 1,500° C. Suchcombustion gases (75) are collected above the converter by a hood (76)and carried away by a metal duct (77). The duct is enlarged in order tofit a number of heat pipes (4) that capture part of the heat andtransfer it to a storage tank (54) filled with a thermal fluid that mayinclude molten salts or eutectics that are stable at those temperatures.Suitable compositions for those molten salts and eutectics are describedin South African Patent No. 2012/05975, Issued on May 29, 2013.

FIG. 8 illustrates another example of heat storage, but one that appliesto continuous heat generation. FIG. 8 shows an optional configurationfor capturing and transferring heat from the ductwork (52) of a powerplant into a storage vessel (54) that allows interruption of heattransfer by simply opening valve (56) thus draining the thermal storagetank into a lower vessel (55). When the thermal fluid is in the lowervessel, heat is no longer being captured from the ductwork. The thermalfluid is stored until it is needed again to capture more heat, at whichpoint pump (57) activates and the thermal fluid is pumped up to thevessel (54) and again allowed to come in contact with the heat pipes(4). In addition, the thermal fluid tank (54) allows a large-diameterheat pipe (58) to capture the heat of the thermal fluid so it can betransferred away for potential use, such as in water purification.

Cooling of Industrial and Chemical Processes

Numerous industrial applications require capturing heat as a means ofcooling and refrigeration. Such industries include but are not limitedto icemaking, brewing, underground mining, pulp and paper manufacture,food processing, beverage production, dewatering during biofuelproduction, and the cooling of chemical and petrochemical reactions thatare exothermic such as in the production of cellulose acetate,nitrobenzene, polyvinyl-chloride resins, carbon disulfide, cumene (fromalkylation of benzene with propylene), ethyl alcohol (from hydration ofethylene), formaldehyde (from methanol using exothermic reactor), phenol(from cumene peroxidation), and propylene glycol (by hydration ofpropylene oxide at 200° C.), acrylic resins (from catalytic oxidation ofmethyl methacrylate), aromatic ketone polymers (from condensationpolymerization reactions), copolyester-ether elastomers, and polyacetalresins, to name a few.

Many industrial cooling operations employ double walled reactors wherethe outer vessel contains a circulating coolant, such as water or athermal fluid, that takes away excess heat from the inner reactor, thuspreventing run-away reactions from exothermic operations. FIG. 9illustrates a typical double-walled reactor for cooling, and while theexample covers the digestion of bauxite into sodium aluminate as a firststep in making alumina, it could also cover many double-walled reactorsused for cooling industrial processes. In FIG. 9, two alternativeconfigurations are presented. FIG. 9(a) illustrates a conventionaldouble-wall reactor, where the outer vessel (64) is filled with athermal cooling fluid (typically water), and surrounds the inner reactor(63) where bauxite is digested with caustic (NaOH). The reactor top (65)closes the reactor and maintains pressure and temperature. The thermalfluid is kept circulating by pump (57), while a heat pipe (4) conductsheat away from the thermal fluid for possible use elsewhere.

FIG. 9(b) illustrates an alternative embodiment where the outer vesselis replaced by a cylindrically shaped heat pipe (4) that contains acapillary wick (12) throughout its entire inner surface area, thusaccelerating the capture of heat and its transport away from reactor.This type of complex heat pipe (58) is discussed in subsequentparagraphs. In cooling applications the working fluid of the heat pipeneed not be water or aqueous fluids, but can be cryogenic fluids, suchas ammonia and the like. Other alternative configurations for capturingheat in cooling and refrigerating applications are covered in SouthAfrican Patent No. 2012/05975, Issued on May 29, 2013, which is herebyincorporated by reference in its entirety.

Cooling towers are generally used for cooling excess heat in thermalpower plants and are commonly employed throughout the chemical andpetrochemical industry. Cooling towers dissipate heat by evaporation andtherefore, substantially contribute to water losses in an industrialoperation. Heat pipes can be used for the augmentation and replacementof cooling towers because of their superior performance in capturing,transferring, and releasing heat. Thus, heat pipes can capture heat fromfluids (gases or liquids) before they enter the cooling tower, thusaugmenting the capacity of the cooling tower and, if sufficient heat iscaptured the cooling tower may be eliminated altogether.

Controlling Temperature in Chemical or Petrochemical Plants

Many chemical and petrochemical industries require precise control ofoperating temperature. In this invention, the means of controllingtemperature are similar to those considered in FIG. 9 above, wherecooling is done in double-walled reactors. Industries requiring closetemperature control include but are not limited to acetaldehyde (fromoxidation of ethylene), acetic acid (from carbonilation of methanol),acetone (from catalytic dehydrogenation of isopropyl alcohol), acrylicacid (from propylene oxidation), acrylonitrile (from ammoxidation ofpropylene), adipic acid (from cyclohexane oxidation), plasticizeralcohols (from hydroformilation of olefins), alkyl amines (fromalcohol/ammonia reactions), benzene (from hydrodealkylation of toluene,1-4 butanediol (from acetylene/formaldehyde reaction), carbon disulfide(from natural gas and sulfur reaction), carbon fibers,carboxymethylcellulose (CMC), cellulose acetate and tri-acetate fibers,chlorinated isocyanurates (from urea pyrolysis), C2 chlorinated solvents(from chlorination of ethylene dichloride), chlorinated methanes, cumene(from alkylation of benzene with propylene), cyclohexane (fromhydrogenation of benzene with hydrogen), di isocyanates andpolyisocyanates (from phosgenation of primary amines), ethyl alcohol(from hydration of ethylene), ethyl benzene (from the alkylation ofbenzene by ethylene), ethylene dichloride (from reacting ethylene withoxygen and hydrogen chloride), ethylene oxide (from oxidation ofethylene), formaldehyde (from methanol using exothermic reactor),hydrogen cyanide, isopropyl alcohol (from hydration of propylene withsuperheated steam), ketene/diketene (from vapor-phase cracking of aceticacid), linear alkylate sulfonates (from sulfonation of linear alkylbenzene with oleum or with sulfur trioxide in sulfuric acid), linearalpha olefins (from ethylene oligomerization), maleic anhydride (fromvapor-phase oxidation of hydrocarbons), methanol (from synthesis gas andcarbon dioxide), methyl ethyl ketone (from the catalytic dehydrogenationof secondary butyl alcohol), phenol (from cumene peroxidation), phosgene(by reacting anhydrous chlorine gas and carbon monoxide), phthalicanhydride (by reacting xylene with oxygen), polyester fibers, polyesterpolyols (by condensation of a glycol and a carboxylic acid or acidderivative), polyethylene, polyglycols for urethanes, polyimides,propylene glycol (by hydration of propylene oxide at 200° C.), propyleneoxide (from chlorohydrin or peroxidation), pyridine and pyridine bases(by reacting acetaldehyde—usually with methanol or formaldehyde—withammonia), sorbitol (by high-pressure catalytic hydrogenation of glucosein autoclaves), terephthalic acid and dimethyl terephthalate, urea,acrylic elastomers,acrylic resins (from catalytic oxidation of methylmethacrulate), amino resins (from the reaction of aldehydes and aminogroups), aromatic ketone polymers (from condensation polymerizationreactions), fluoropolymers (from tetrafluoroethylene reacting with acid,and surfactants), copolyester-ether elastomers, nylon resins, polyamideresins, polyacetal resins, polycarbonate resins, PBT resins (frombis-(4-hydroxybutyl)-terephthalate-BHBT), PET polymers (bypolycondensation of ethylene glycol with either dimethylterephthalate orterephthalic acid), unsaturated polyester resins, and polystyrene resins(using free-radical polymerization of styrene with an initiator andheat)

Using Heat Capture for Delivery at Remote Locations

Embodiments of the invention include systems, methods, and apparatus forheating underground geological formations, such as oil deposits (e.g.,enhanced oil recovery—EOR), without requiring water, CO₂, or steaminjection. Preferred embodiments provide a broad spectrum of heat pipesthat operate within the temperature range of 120° C. and 1,300° C. orhigher, and that provide for fully automated heat recovery attemperatures similar to that range over several hours, days or monthswithout user intervention. For example, systems disclosed herein can runwithout user control or intervention for 1, 2, 4, 6, 8, months, orlonger. In preferred embodiments, the systems can run automatically for1, 2, 3, 4, 5, 6, 7, 8 years, or more.

FIG. 10 illustrates the use of a heat pipe for purposes of EOR. In FIG.10, the surface site (1) is assumed to have a drill hole (3) that wasalready in place or drilled specifically for the heat pipe, and a heatpipe (4) that reaches from the surface to the oil formation (2). Duringoperation, heat is provided to the top of the heat pipe. The heat pipeefficiently transfers such heat directly from its top to its lowerportion which is in contact with the oil strata. Since sedimentary oilformations can be located at substantial depth, the heat pipe (4) mustbe sufficiently long for it to reach into that formation. Therefore, animportant problem to solve is how to design and manufacture such HP andhow to insert a very long pipe into a vertical or inclined drill holewithout excessively bending the pipe and thus damaging it.

FIG. 11 describes one possible method for placing a long heat pipe intoa drill hole. In FIG. 11, a number of buoyant balloons (5) are used atsuitable intervals along the length of the pipe (4) to neutralize itsweight and thus prevent it from bending when lifting one of its ends.The actual lifting can be done with a helicopter (6) or similar airbornesystem (e.g., a drone). Once the heat pipe is aligned with the drillhole (3), its neutral weight makes it easy to lower it into position,gradually removing the individual lifting devices (5) from the pipe (4),until the pipe reaches the oil formation (2).

FIG. 12 shows an alternative embodiment for placing a heat pipe down adrill hole. In FIG. 11, the heat pipe 4 is wound around a circular wheel25 with sufficient radius to minimize the curvature of the pipe and thusprevent damage to its internal mechanism. As the wheel is rotated, theheat pipe is then lowered into the drill hole 3.

Once in place, the heat pipe is ready for transferring heat from thesurface to the oil formation directly without the need for pumps,external recirculation loops, or other mechanisms. Heat can be providedto the upper portion of the pipe on the surface by direct combustion offuels (e.g., natural gas, oil), by solar heating through solarconcentrators or parabolic troughs, electrical, geothermal sources,steam, waste heat at elevated temperatures, or any other type of energysource. Since heat pipes excel at axial heat transfer at rates thatapproach the speed of sound, the heat absorbed from surface sourcesrapidly reaches the oil formation where such heat is released.

An optional configuration entails using a heat pipe as described in theabove paragraph together with steam injection. This allows the steam tomaintain a high temperature throughout the length of the heat pipe, thusminimizing wall heat losses, while enhancing heat transfer anddelivering higher temperature heat at the bottom of the heat pipe. Inaddition, steam condensation provides liquid water at the oil formationthat enhances flow. This type of configuration can prove useful whenthere is a need for additional heat delivery or when the number of drillholes for EOR is limited.

Using Heat Capture for Delivery in Geothermal Fields

In other applications, such as the recovery of heat from geothermalfields, preferred embodiments include either heat pipes, thermosyphons,loop heat pipes, or pulsating heat pipes that operate within thetemperature range of 250° C. and 1,300° C. and that provide for fullyautomated heat recovery at temperatures similar to that range overseveral hours, days or months without user intervention.

FIG. 13 illustrates two embodiment options for extracting heat from ageothermal field. Geothermal sources typically derive heat energy from adeep magma chamber (27) (not drawn to scale in FIG. 13), which heat ageothermal formation (26) that may have significant moisture or besubstantially dry. FIG. 13(a) assumes a wet geothermal formation, sothat liquid water in the drill hole (3) can transfer heat directly tothe heat pipe, pulsating heat pipe, or thermosyphon (4). As demonstratedin subsequent paragraphs, the heat pipe, thermosyphon, or pulsating heatpipe (4) provides a highly efficient mechanism for heat transfer fromthe geothermal formation (26) to the surface, where such heat can berecovered at temperatures similar to those prevailing at depth andutilized directly without the need for either heat exchangers or watertreatment.

FIG. 13(b) illustrates an alternative embodiment for geothermal heatrecovery when the geological formation is either very dense, or has lowporosity or permeability, or lacks sufficient moisture to assist in heatconduction at depth. In those cases, the bottom of the drill hole (3) isenlarged at the bottom (28) in order to provide a greater surface areafor thermal conductivity. To further increase thermal conductivity, thisbottom portion of the hole can be partially filled with water (29) orother high thermal conductivity fluids. Furthermore, in order topreserve the high temperature in a geothermal field, it would beadvantageous to cap the drill-hole at the top with a valve (30), so asto maintain the pressure and temperature prevailing at the geothermaldepth, thus allowing the heat pipe, pulsating heat pipe, or thermosyphon(4) to transfer heat at the maximum possible temperature to the surface.

Description of Heat Transfer from an Industrial Source

Other embodiments capture heat from industrial plants and transfer it tosites that can use that heat at distances of tens to hundreds tothousands of feet. These systems can operate within the temperaturerange of 80° C. and 1,300° C. and provide for fully automated heatrecovery at temperatures similar to that range over several hours, daysor months without user intervention.

FIG. 14 shows an embodiment for transferring heat in an industrialsetting. In a typical industrial plant (31), a source of waste heat(32), which can include a power plant, a boiler house, an exothermicprocess vessel, or a chemical reactor that can be used to provide heatby means of heat pipes (4) which transfer such heat with minimal lossesin temperature to remote places (33) which can include steam generationsites or other process vessels that require heat.

The chemical process industry covers many hundreds of chemicals andpetrochemicals that either utilize highly exothermic processes, requiretemperatures of several hundreds of degree centigrade, or produceproducts that must be cooled or refrigerated rapidly. Examples includebut are not limited to the manufacture of acetaldehyde, acetic acid,acetic anhydride, acetone, acetonitrile, acetylene, acrylamide, acrylicacid, acrylonitrile, adipic acid, alkyl amines, alkylbenzene, ammonia,aniline, ketone polymers, benzene, benzylchloride, bisphenol A,beutanediol, butylacetate, caprolactam, carbon disulfide, celloloseacetate, cellulose ethers, chlorinated isocyanurates, chlorinatedsolvents, chlorobenzenes, chlorinated methanes, cresols, xylenols,cumene, cyclohexane, dimethylformamide, epichlorohydrin, epoxy resins,ethanolamines, ethyl acetate, ethanol, ethyl benzene, ethylchloride,ethylene, ethylene dichloride, ethylene amines, ethylene glycol,ethylene oxide, fluorocarbons, formaldehyde, fumaric acid, furfural,glycol ethers, Hexamethylenediamine, hydrogen cyanide, hydroquinone,isophthalic acid, isopropyl alcohol, ketene, alkylsulfonates,alphaolefins, lignosulfonates, maleic anhydride, melamine, methanol,methylethyl ketone, methyl methacrylate, nitrobenzene, Nylon resins,phenol, phenolic resins, phosgene, phthalic anhydride, polyamide resins,polyacetal resins, polyalkylene glycols, polycarbonate resins,polyesters, polyethylene, polyglycols, polyimides, polypropylene,polystyrene, polyvinyl alcohols, propionic acid, propylene glycol,propylene oxide, pyridine, silicones, sorbitol, styrene, terephthalicacid, urea, vinyl acetate, vinyl chloride, and zeolites.

Another type of industrial application involves power plants,particularly those fueled by coal. These plants generate substantialvolumes of combustion gases that require progressive treatment steps toreduce pollutants. Typically nitrogen oxides (NOx) are generated duringthe combustion process and need to be reduced by adding ammonia oramines which reduce the NOx to nitrogen gas. Next, the fly ash particlesneed to be captured and removed, which is normally done withelectrostatic precipitators or baghouses, or both. The flue gases alsocontain significant sulfur compounds from the original coal, which isnormally handled in a flue gas desulfurization (FGD) system involvingscrubbing. In spite of these various treatment steps, the flue gas in acoal-fired power plant contains very large amounts of low-grade heat attemperatures in the range of 330° F. to 400° F. that can be tappedwithout unduly affecting the normal operation of the plant.

Other examples of heat capture, transfer, and release include:

-   -   In thermal power plants,    -   The augmentation and replacement of cooling towers    -   The augmentation and replacement of large condensers    -   Extracting heat as steam and “hot furnace gas” to optimize cycle        efficiency    -   Recovering heat from the boiler house in small power plants    -   In hot-pond power generation, using heat pipes to transfer heat    -   Preheating pre-combustion gases    -   Capturing heat from boiler blow-down    -   In nuclear power plants,    -   Cooling of spent-fuel storage    -   Cooling of reactor core    -   Augmentation and replacement of steam condensers        -   In natural gas compression stations    -   Recovering heat from large compressors    -   In underground mining    -   Cooling deep working sites    -   In solution mining    -   Heating underground formation to increase solubility    -   In plywood and OBS production    -   Drying of raw materials    -   In the heat management of industrial processes, such as    -   bio-fermentation    -   fertilizer production (e.g., urea)    -   In industrial gas production    -   Compressor heat in argon, nitrogen, oxygen, CO₂ production    -   Gas liquification    -   Coal gasification and syngas—Fischer-Tropsch process    -   In military applications, such as    -   Stationary generators    -   Mobile engines, such as vehicles    -   Engines on ships    -   Mobile/deployable heat pipe runway for both, cooling and heating    -   In solar applications    -   Capturing, transferring, and releasing heat in solar        concentrators    -   Cooling of photovoltaic arrays    -   In metallurgical applications    -   Crystal pulling (e.g., silicon) using radian heat    -   Continuous casting of steel and other metals using radiant heat        and conduction    -   Heat shielding by transferring heat away from the heat shield    -   Cooling the molds in sand casting    -   Cooling the laser head in laser cutting    -   Miscellaneous other applications, including heat sensitive        industries in SIC code, such as    -   Heat recovery from semi-conductor processing    -   Rubber manufacturing, e.g., vulcanizing    -   Oil refineries, including coker, distillation towers, and        chemical reactors    -   Augmenting and replacing HVAC systems for cooling and heating of        residential and industrial buildings    -   Freeze protection for agricultural applications, such as grapes        and citrus.    -   Decomposing undersea methane hydrate for gas production.

Since any type of heat pipe is exceedingly effective at heat transfer,the following section focuses on heat pipes, and how to improve theiraverage performance so they can be applied not only to conventionalapplications, such as stabilizing Alaskan permafrost, but also in avariety of industrial applications including but not limited todesalination, industrial transfer of heat, cooling, refrigeration, andthe like.

About Heat Pipes

Clearly, heat pipes allow effective thermal transfer to be done. Theheat pipes are driven by the temperature difference between theircondensing and boiling ends (the ΔT) which is sufficient to maintain avery high heat flux through the heat pipe. Commercially available heatpipes transfer large amounts of heat (e.g., >200 W) and typically haveΔTs of the order of 8° C. (15° F.), or higher at higher power output,although some have ΔTs as low as 3° C. The ΔT is not critical for EOR orgeothermal applications because the difference in temperature between asurface heat source and the geological formation is several hundreds ofdegrees, but a low ΔT is generally desirable to optimize overall thermalefficiency. It is therefore useful to examine the thermal phenomena in aheat pipe. Insert working fluid here (92)

An important factor in maintaining a low ΔT is limiting the wall heatlosses, which are a function of the surface area (and thus on thelength) of the pipe and the thermal conductivity of the wall materialand the media surrounding the HP. This need is not critical for normalHP pipes but is important for very long HP as claimed in thisapplication. FIG. 15 illustrates different possible embodiments ofsurface insulation for a long heat pipe so that most of the heat istransferred to the cool end and very little is lost along the walls ofthe HP in the middle section. In the embodiment illustrated in FIG.15(a), a good insulating coating (7) is used over most of the surfacearea, except for the areas where the heat pipe (4) either absorbs orreleases heat. Adequate insulators for relatively low temperature (<150°C.) include the thermal insulator materials such as those used in steampipes. Adequate insulators for high temperature operation can includevarious insulating bodies with ceramic compositions, such as zirconia,alumina, magnesia, and similar compositions. An optional configurationfor superior insulation is shown in FIG. 15(a) and entails a ceramicmaterial containing close pores. FIG. 15(b) shows another embodimentwhich consists of a tube enclosure (7) under partial vacuum. Thisenclosure provides superior thermal insulation, plus the advantage of anexternal vacuum that neutralizes the structural strain of the internalvacuum of the heat pipe. The type of enclosure tube can be similar tothose utilized in the heat collector tube of parabolic solarconcentrators. FIG. 15(b) illustrates an embodiment that includes astructural support sleeve (24) that surrounds the heat pipe (4) atregular intervals to prevent the weight of the heat pipe from overcomingthe structural resistance of the heat pipe assembly, particularly forhigh temperature operations. Such structural support can serve the dualpurpose of assisting in neutralizing the weight of the heat pipe bothduring its insertion into its final location and during operation.

FIG. 15(c) illustrates another embodiment for extending the length ofheat pipes with minimal loss of heat transfer performance. In FIG. 15(c)the heat pipe (4) ends with a smaller diameter tube (40) that fits intoa hollow semi-cylinder which is the end of another heat pipe. Thesurface area of the two heat pipes allows heat to transfer from one heatpipe to another, and thermal losses are minimized by a flexibleinsulating blanket (not shown). FIG. 15(d) illustrates an alternativeconfiguration for connecting two or more heat pipes (4) into a longerheat pipe using small diameter or capillary size endings of each heatpipe (40). This type of configuration utilizes a common feature of heatpipes, namely that the internal shape of a heat pipe has littleinfluence on the heat transfer performance and functionality of the heatpipe. Both types of configuration lead to “articulated” heat pipes thatare designed to pivot and bend at the junction of two or more heatpipes, thus allowing very long heat pipes to follow a non-straight path.

FIG. 16 illustrates a typical commercial heat pipe (4), which ordinarilyconsists of a partially evacuated and sealed tube (10) containing asmall amount of a working fluid (11) which is typically water, but whichmay also be an alcohol or other volatile liquid. When heat in the formof enthalpy is applied to the lower end of the heat pipe, the heat firstcrosses the metal barrier (10) and the internal wick (12) and then isused to provide the heat of vaporization to the working fluid (11) whichpermeates the entire surface of the wick. As the working fluidevaporates, the resulting gas (steam in the case of water) fills theevacuated tube and reaches the upper end of the heat pipe where the ΔTbetween the inside and the outside of the heat pipe causes condensationand, thus the release of the heat of condensation to the outside of theheat pipe. To facilitate continuous operation, the inside of tube (10)normally includes a wick (12) which can be any porous and hydrophiliclayer that transfers the condensed phase of the working fluid back tothe hot end of the tube.

An improvement in the ability to capture heat is the use of metal oxidesand/or pigments that are dark or black and that absorb heat morereadily, particularly in the case of radiation heat. One advantage of aheat pipe having a black exterior coating is that such black surfacealso excels in radiating heat at the cold end of the heat pipe.

Experimentally, the largest barriers to heat transfer in a heat pipeinclude: first the layer immediately adjacent to the outside of the heatpipe (the boundary layer), second the conduction barrier presented bythe material of the heat pipe, and third, the limitation of the wickmaterial to return working fluid to the hot end of the heat pipe.However, in EOR applications, the boundary layer adjacent to theexterior of the heat pipe is minimal for two reasons: first, because ifdirect heating is used or steam or pressurized hot water are not used,the thermal barrier becomes far less significant, and second because, onthe oil formation side, any water tends to be quite saline which canreadily collapse the molecular double layer responsible for most of thebarrier. FIG. 17 illustrates a high-performance heat pipe that minimizesthese barriers. Note that the axial wick reduces the thermal barriernormally present in a conventional wick that is adjacent to the wall ofthe heat pipe.

In FIG. 17, the heat pipe (4) is shown in a vertical position with theheat input at the top and heat release at the bottom. The heat transferbarrier that is adjacent to the exterior of the heat pipe can beminimized as described in the above paragraph. The heat conductionbarrier through the metal casing of the pipe can also be minimized byusing a very thin metal foil (10) instead of the solid metal tube ofmost heat pipes. Mechanical support for the metal foil must besufficient to sustain moderate vacuum and is provided by a metal screen(13) that provides additional functionality by increasing the internalsurface area available for providing the necessary heat ofcondensation/evaporation. An internal wick (12) is also provided toassist in the evaporation of the internal fluid by its large surfacearea and open porosity. Also, given the long distance that the condensedworking fluid must travel inside the pipe, there is an additional axialwick structure (14) at least partially not attached to the walls thattransfers fluid through capillary action, but independently from thesurface wick action.

During operation, heat enters near the top and traverses the thin metalfoil (10). The thinness of the metal foil facilitates heat transferbecause thermal conductivity is an inverse function of the thickness ofthe material through which heat must travel. Upon reaching the internalwick (12), heat rapidly evaporates the working fluid that is present inthe wick. The saturated vapor travels rapidly through the internalvolume of the heat pipe and reaches the opposite end of the pipe wherethe slightly lower temperature causes the condensation of the vapor backinto the working fluid. In the process, the heat of vaporization hasbeen transferred from the top of the heat pipe to the bottom. Thecondensed working fluid then flows by capillary action toward the hotend of the pipe through both the surface wick (12) and the central axialwick (14), thus providing the necessary volume of flow for maintaining alarge heat transfer.

FIG. 18 shows a graphical comparison of two heat pipes: one aconventional and one a novel design. In the conventional heat pipe, themain problem is maintaining a wick structure (12) uninterrupted over theentire length of the pipe. Ordinarily, this is not a problem with pipesa few feet in length or shorter. It becomes a serious difficulty whenthe length exceeds such dimensions. The novel design obviates thisproblem by having an axial capillary wick (14) that does not requiresintering or high thermal conductivity, but that may consist of anyporous material that is wettable by the internal working fluid. Ineither case, the objective is to be able to transfer heat energyefficiently from the heat source at the top of the heat pipe to theapplication area at the bottom of the heat pipe. That objective isdifficult if not impossible to achieve with a conventional heat pipe,unless the internal wick can function without interruption. Anotherproblem/limitation of HP is manufacturing very long tubes. Making longtubes is normally accomplished by either welding shorter tube lengths,or threading them, but in either case, the problem of leakage arises,especially when conventional pipes are partially evacuated before finalassembly.

Internal wick materials include sintered copper spheres, metal groves,metal screens, and other materials that contain a well-defined porosity.

FIG. 19 illustrates an alternative embodiment that obviates the need forextremely long heat pipes. In the cross sectional view of FIG. 19,shorter heat pipes (4) are assembled with intermediate reservoirs (8)that contain a thermally conductive fluid (9), which transfers heat fromone heat pipe to another, thus lengthening the distance over which heattransfer occurs. However, this embodiment requires that the intermediatereservoir be hermetically sealed to prevent loss of heat transfer fluid(9). In addition, thermal losses will necessarily increase with thistype of embodiment because of the increase ΔT at each junction, and thehigher thermal wall losses due to the surface area of the intermediatereservoir and its temperature. Yet, the proposed embodiment offers apractical solution to heat transfer over very long distance, especiallyin EOR applications since pipe joining is a common activity andhigh-temperature heat is normally available. The type of transfer fluidcan be any heat conducting liquid that is chemically stable at thetemperatures involved in the heat transfer junction, such as DowTerm®,certain eutectic salt mixtures, and the like. Those familiar with theart will also recognize that similar embodiments involving the joiningof short heat pipes into longer ones while maintaining hermetic sealsare also possible and therefore the proposed embodiment is merelyexemplary and is not intended as a limitation on the scope of theinvention.

The composition of the working fluid inside a heat pipe generallydetermines the temperature range of the heat pipe or thermosyphon. Lowtemperatures involve organic compounds such as ammonia, alcohols,ketones, aldehydes, or aromatic hydrocarbons that boil at temperatureslower than ordinary water or aqueous solutions. For high-temperatureranges, certain metals like sodium, potassium, magnesium, aluminum,lead, zinc, and their alloys provide working fluids that can work attemperatures in excess of 1300° C. Another option is to use salts andmixtures of salt that sublimate as a working fluid for both, high andlow temperature heat pipes. Also included are metal oxides, borateshaving different hydration levels.

FIG. 20 illustrates a method for making heat pipes of any length, andone that is especially suitable for the manufacture of very long heatpipes. The method begins with a tubular scaffold (13) made of a metalscreen with wires that are strong enough and openings that are smallenough to maintain structural integrity of the finished heat pipe onceit is sealed under partial vacuum. Normally, mesh sizes of the metalscreen in the range of 24 to 150 mesh could be suitable to maintainpartial vacuums of the order of 0.1 bar. If higher vacuum is desirable,the size of the metal screen can be down to 325-400 mesh, and one canprovide a double screen surface with larger screen holes on the insidesurface of the tubular scaffold that will add rigidity to the externalscreen surface. Those familiar with the art will realize that there aredifferent ways to manufacture such tubular scaffold: it can bepre-formed which limits the overall length to several hundred feet, orit can be woven in situ for longer distances.

Once the tubular scaffold is formed, it is inserted into a furnace (19)that can sinter or weld the finished surface of the heat pipe which isallowed to rotate, as shown in the diagram of FIG. 20. Next, a metalstrip (17) made of thin metal foil that includes a slightly thinnerstrip of sintered wick material (18) on one side is continuously woundover the tubular scaffold, so as to form a tube. The winding angle ofthe metallic strip (17) will be determined by the width of the strip(17), and the degree of strip overlapping required to completely sealthe winding surfaces together. The furnace (19) is essentially the nextto the last step in forming a tube with an inner wick layer. Once thetube is complete, an axial wick can be placed, the working fluidinserted, and the pipe can be evacuated and sealed. Alternatively, theaxial wick and the tube can be manufacture simultaneously.

FIG. 21 provides cross sectional views of two embodiments for winding along distance tube with an inner wick surface. In FIG. 20(a) the wick(18) consists of strip of sintered spheres (17), and shows two upperstrips of a porous flexible weave (20) that protrude over the edge ofthe wick. When wound around the tubular scaffold the weaves make contactwith adjacent weaves, thus providing a continuous porous layer thatconstitutes a continuous capillary surface. This prevents the inner wickmaterial from being isolated in any section of its axial length. Analternative embodiment is described in FIG. 21(b), where the inner stripof wick material is placed at a slight angle with respect to thevertical line, so as to be wider than the thin metal foil being wound,so as to ensure proper contact of the inner wick material. Of course,this can cause a slight separation between the thin metal foils duringwinding, which can be sealed with a thinner strip of foil (21) that iswound around the pipe just before it enters the welding furnace, asillustrated in FIG. 22.

FIG. 23 illustrates an embodiment of the axial wick (12) that mayconsist of a single cylindrical porous body, a coaxial cylinder with aninner metal wire to provide rigidity, a coaxial cylinder where thecapillary action derives from small beads made of glass, ceramic, ormetal, or combinations thereof. To prevent bending of the axial wick andmaintain its separation from the inner walls of the heat pipe (4), aseries of radially spaced supports (22) is placed along the length ofthe wick prior to its insertion into the heat pipe. Such supports aregenerally thin sections that do not unduly reduce the free inner volumeof the heat pipe, and thus do not reduce the mass flow of vapor alongthe length of the heat pipe.

An alternative method for manufacturing a suitable wick is by using acopper or other metal precursor. A metal precursor is a chemicalsubstance that upon heating decomposes into a metal. In the case ofsintered copper wicks, the precursor can be copper beta diketonate(CBDK) or copper acetylacetonate (CAA), both of which decompose intomicron-sized copper particles upon heating in a reducing atmosphere. Ingeneral any organic precursor that can be decomposed, or any ionicprecursor that can be electrodeposited can be candidates. A suitablewick can be made by slurrying micron-sized copper particles in CBDK orCAA and spreading the slurry into the inside surface of a copper tube orcopper strip. The excess liquid is drained away, so the solid metalparticles are subsequently held by surface tension of the funicularrings that form in the contact points of the metal particles. Uponheating in a reducing atmosphere, the CBDK or the CAA decomposes intocopper that welds into the contact points of the metal particles, thuscementing them in place. Alternatively, providing a suitableelectro-potential, Cu ions can be deposited to provide the desired glue.Numerous metal precursors are available for decomposition into differentmetals, and normal thermal diffusion will allow such precursors tocement similar and dissimilar metals, as long as the metallic particlesand the precursor metal have some solubility with each other. Forexample, deposition of CU on Cu or Sn on Cu can both provide the goodthermal contact via Cu or CuSn alloys bridges.

Following the installation of the axial wick, which is optional butdesirable in a long heat pipe, the working fluid is inserted so it cansaturate the inner surface of the wick and the volume of the axial wick.The volume of working fluid can be 0% to 25% higher than required forwick saturation, and in cases where the evaporated working fluid canbecome superheated in its vapor form, the excess working fluid canexceed 25%.

A potential problem may arise with the wick structure in very longvertical heat pipes because of the need to maintain capillary actionagainst the forces of gravity. The height of a capillary rise, h, isdefined by:

${h = \frac{2\gamma \; \cos \; \theta}{\rho \; g\; r}},$

where γ is the liquid-air surface tension (force/unit length), θ is thecontact angle, ρ is the density of liquid (mass/volume), g is localacceleration due to gravity (length/square of time[26]), and r is radiusof tube.For a water-filled glass tube in air at standard laboratory conditions,γ=0.0728 N/m at 20° C., θ=0° (cos(0)=1), ρ is 1000 kg/m³, and g=9.81m/s². For these values, the height of the water column is

$h \approx {\frac{1.48 \times 10^{- 5}}{r}{m.}}$

Thus for r=0.0002 m (0.2 mm), h=0.074 m, and for r=0.000002 m (2micron), h=7.4 m, and for r=0.000000002 m (2 nm), h=7,400 m. However, inactual industrial practice laboratory conditions do not necessarilyapply: the value of surface tension normally decreases with temperatureand the contact angle is rarely 0°, although by keeping the wick surfaceclean and using working fluids that are aqueous such values can beapproached. The largest factor in maintaining capillary action, however,remains the radius of the capillary. Therefore, the wick pore size invery long heat pipes needs to be in the range of several nanometers andnot in the micron range as it is normal for conventional HP. However,this is not a problem encountered with pulsating heat pipes orthermosyphons that do not have wick structures. The practicalimplication in terms of manufacturability suggests sintered wicks madeof nano-particles or the use of nanotubes or nano-sized structuredpowders or films of similar size.

The final stages in making a heat pipe involve evacuating it by applyingvacuum, and sealing it by crimping or welding. FIG. 24 illustrates analternative embodiment to the sealing operation, and consists ofinstalling a valve (23), that allows periodic checking of vacuumconditions during operation.

FIG. 25 illustrates an alternative embodiment for making advanced heatpipes, those that due to thin walls and special wick structures exhibitsuperior thermal transfer performance, and are easy and inexpensive tomanufacture. In FIG. 25(a), the manufacturing process begins with twothin foils (35) that are first coated with wick material (18). Becausethe wick is formed on a planar surface before the heat pipe is made, thewick structure can include different size materials. For example, nextto the foil surface, the wick material can consist of nano particles inthe range of a few nanometers up to 100 nanometers, depending on theultimate vertical length of the heat pipe. In the case of common metals,such as copper and its alloys, this initial layer of nanoparticles isthen sintered at temperatures lower than for conventional HP, of theorder of 500-700° C. In our case it could be several hundred degreeslower. Alternatively, the initial layer of nanoparticles can be held inplace by an adhesive that can be subsequently pyrolized and/orgraphitized at temperatures of the order of 800-850° C. Also they can besupported by a material that maintains its structure at the temperaturesand vapor pressures used. For example, it could be 20 nm porous zirconiananosponges decorated with nanofilms or nanoislands of Cu or Ni if wateris the working fluid. Next, a second layer of wick material, such asparticles in the range of 1 to 100 microns, can be deposited on the foilsurface and the process of sintering or pyrolysis can be repeated,thereby increasing the amount of mutual attachment. Alternatively, asecond layer of wick material can consist of copper gauze, whichprovides a superior pore structure for the wick. That gauze material canthen be joined with the lower layer of wick material. Thus, the wick canbe built up sequentially to contain different layers of differentporosity and permeability. Thus, this type of heat pipe can have lengthsup to 10-14 km.

Once the wick material has been formed onto the foil, a number ofmetallic scaffolds (13) can be placed between the two thin foils (35),so as to form separate cylindrical surfaces separated by flat foilsurfaces, as illustrated in FIG. 25(b). The foil surfaces that separatethe individual scaffolds should then be sealed by soldering or crimping,or both. In FIG. 25(b) one end of these cylindrical shapes is closed andsealed by crimping or soldering, or both. Partial vacuum is then appliedto ensure good contact between the scaffolding material and the foilcontaining the wick layer(s). Ordinarily, such vacuum is sufficient toprovide good contact between the foil and the scaffold, but subsequentsintering can effectively weld these surfaces together. The resultingcylindrical shapes thus become heat pipes (4) connected by thin metalfoils (35). These can be used as such in applications that require largesurface areas and effective heat transfer coefficients.

FIG. 25(c) illustrates the option of separating the connected heat pipeassembly into individual heat pipes, each having a couple of thin metalflaps for added surface area. However, such foil surfaces can be trimmedor cut away, as shown in FIG. 25(d), to ultimately make individual heatpipes, as shown in FIG. 25(e).

FIG. 26 illustrates an optional configuration for transferring largeamounts of heat over long distances, particularly at depth or invertical arrangements. In FIG. 26, the heat pipe (4) consists of a“pulsed” heat pipe (See, “An Introduction to Pulsating Heat Pipes.”Electronics Cooling Magazine. www <dot> electronics-cooling <dot>com/2003/05/, which is incorporated herein by reference in itsentirety). In FIG. 26, heat is delivered at one end of the heat pipe (4)by any source of heat energy. The heat pipe (4) is partially filled witha liquid fluid (45) that evaporates as vapor (46) when heat is absorbedby the heat pipe. The vapor (46) increases the internal pressure of theheat pipe and causes both vapor (e.g., steam bubbles) and liquid plugs(e.g., slugs) to move in one direction, because a one-directional valve(47) prevents flow in the other direction. The internal flow of vaporand liquid transports heat by mass transfer to the other extreme of theheat pipe assembly which is at a lower temperature. This heat transfercauses heat to be released by condensation of vapor to liquid (therelease of the latent/sensible heat contained in the liquid phase). Asheat is transferred, additional vapor is condensed into liquid phase andthat liquid continues to flow in response to the pressure pulses.

What distinguishes the present invention from conventional pulsatingheat pipes is that the heat pipe can be manufactured according to theprinciples noted in the previous discussion regarding long-distance heatpipes in FIGS. 20 through 22, except that the reinforcing screens (13)would be placed external to the metal foil (17), so as to providestrength to resist the internal pressure pulses, and the lack of a needfor an internal wick material (18). Alternatively, pulsating heat pipescan be assembled using conventional methods of joining pipes. Additionaldistinguishing features include the use of specialty coatings on theinner surface of the heat pipe to promote evaporation and boiling,and/or on the outside of the heat pipe to enhance heat transfer to ageologic formation or other heat requiring application. In addition, theexternal surface of the pulsed heat pipe can be thermally insulated,except at the ends. Thus, this type of heat pipe can have lengths up to10-14 km.

Effective heat transfer that occurs without significant temperature lossis also attractive for thermal power plants that have substantialvolumes of waste heat available, but at temperatures that are normallytoo low for various industrial applications. However, a novel technologyhas been developed by Sylvan Source, Inc, (U.S. Pat. No. 8,771,477, andpatent application No PCT/US2012/054221, with international filing dateof 7 Sep. 2012, and priority date of 9 Sep. 2011, incorporated herein byreference in its entirety) that can purify a broad range of contaminatedwaters using very little heat energy, and that technology can becombined with heat capture to provide useful heat capture with waterpurification.

However, for such innovation to be effective the capture of heat, itstransport to where it can be used, and its subsequent delivery must takeeffect with a minimum of temperature loses. Heat pipes, thermosyphons,and pulsating heat pipes provide a practical solution, provided that theheat pipe system can fulfill all three functions simultaneously andwithout intermediate steps. Thus, there is a need for long-distance heatpipes that can capture low-grade as well as higher temperature heat,transfer such heat energy to a larger diameter heat pipe with notemperature loss, and deliver such heat energy to a number of smallerdiameter heat pipes for actual utilization, again not sufferingsignificant temperature loss. One way in which this can be accomplishedis by having a number of smaller diameter heat pipes (4) seamlesslyconnected to a larger diameter heat pipe (58), and in turn connected toa heat delivery system consisting of smaller diameter heat pipes (4), asillustrated in FIG. 1.

Clearly, for a complex heat pipe to function as a single unit it isessential that the mechanism for returning the working fluid to the hotend of the heat pipe must not be interrupted. That means that theinternal wick that functions by capillary action must be inter-connectedthroughout the various joints between the heat pipe elements. Sincejoining metallic heat pipes would normally be accomplished by weldingthe external encapsulating material and such welding cannot be used tojoin the sintered wick, the question becomes “how to provide forcapillary continuity” when joining dissimilar heat pipes. FIG. 27illustrates a method to accomplish this purpose.

FIG. 27(a) shows how to join two heat pipes (4) and (58) of differentdiameter. A hole is cut into the larger heat pipe (58) so that thesmaller heat pipe (4) can fit precisely. A doughnut-shaped gel (48)containing particles of the same size as the wick material is placed atthe end of the smaller heat pipe (4), as shown in FIG. 27(b), and thetwo heat pipes are joined as shown in FIG. 27(c). FIG. 27(d) shows anenlarged cross-sectional view of the two heat pipes and the gaps thatexist in the wick material. FIG. 27(e) illustrates what happens whensolder (49) or a weld is applied to the external surfaces of the twojoined heat pipes: the gel material liquefies and evaporates, but notcompletely, thus allowing capillary action to draw in the suspension ofmicroscopic particles so as to fill the gaps in capillary material (12).The heat of soldering or welding is sufficient to evaporate all of theliquid used to suspend the microscopic particles, leaving behind smallfunicular rings that can pyrolyze, thus holding the new wick particlestogether (50), as shown in FIG. 27(f). Additional heat can then beapplied, if needed, in order to sinter the additional wick particlestogether. And of course, all of the above requires that there is novacuum at the time the heat pipes are being joined. An example of a gelthat could perform as indicated is a silica gel, which would leavewelding spots between the new wick material consisting of silica—ahydrophilic substance that would facilitate capillary continuity.However, the silica would likely dissolve and move from the hot to thecold side of the heat pipe, so a preferred material would be a silicagel that has alumina particles, zirconia or rare earth particles insuspension, so they permanently weld the wick together.

Another important feature of an advanced heat pipe, particularly onethat integrates several small diameter and large diameter heat pipes, isthe ability to stop the transfer of heat at will, such as in industrialsituations where the main plant must be disconnected from the heattransfer mechanism. FIG. 28 illustrates one mechanism of controllingheat transfer in an advanced, complex heat pipe. As shown in FIG. 28(a)a simple valve (60) that can be electronically or remotely controlled isattached to the inside of the large diameter heat pipe (58) and, whilevalve (60) is open, the heat pipe continues to transfer heat asdesigned. FIG. 28(b) illustrates what happens if the valve closes inresponse to an external actuator: the flow of gaseous working fluidstops entering the small diameter heat pipe (4) and thus heat transferis interrupted.

An optional configuration of advanced heat pipes includes hybrids ofheat pipes with pulsating heat pipes and/or loop heat pipes that combinethe best features of each type of heat pipe into a single entity withsuperior performance. For example, a combination of a pulsating heatpipe can provide for optimum heat capture and release, while a standardor loop heat pipe that is an integral element provides for optimum heattransfer. Such a hybrid can include thin wall thickness at the heatcapture and release ends, and thicker walls with or without thermalinsulation to prevent long-distance losses, and a common wick materialthat ensures continuous fluid communication inside the hybrid pipe dueto capillary action. Furthermore, the capillary wick can consist of anaxial or spirally wound wick that periodically touches the internalwall, thus maintaining capillary continuity throughout the length of theheat pipe. Such flexible wick can be used to join different heat pipesprior to welding, thus also maintaining capillary continuity.Alternatively, the wick material can be grooved for the long-distancesection of the heat pipe, thus providing for different wick structuresthat optimize each function of the heat pipe: heat capture, transfer,and release. Another option involves the use of metallic screens thatcan weld onto slightly larger or smaller diameter screens that providefor capillarity.

Heat Release Using Heat Pipes, Spreader Heat Pipes, Thermosyphons, andPulsating Heat Pipes

The release of heat involves the same principles as the capture of heat,except that in the case of heat pipes, particularly in conventional heatpipes, the execution of those principles are in the reverse order. Thus,releasing heat from a conventional heat pipe involves first thecondensation of the internal vapor at the cold end of the heat pipe,then the transfer of that heat via thermal conductivity through the wickmaterial and subsequently through the encapsulating tube which isnormally a metal or alloy, and ultimately the dissipation of that heatto the medium outside the heat pipe. In the case of advanced heat pipeswhich may contain multiple wick layers of different porosities, thethermal conductivity will depend on the thickness of each wick layer andthe thermal conductance of the wick material. In the case of pulsatingheat pipes and thermosyphons, when there is no wick, the thermalconductivity through the encapsulating tube will depend on whether theinternal fluid is in liquid or gaseous form, as well as the thermalconductance of the tube and its thickness.

The numerous possible configurations described in the previousparagraphs have distinct advantages for releasing heat efficiently, suchas:

-   -   The use of thinner wall thickness in the encapsulating material        for heat pipes minimizes temperature loss while enhancing the        amount of heat being transferred per unit of surface area, as        illustrated in FIGS. 17, 20, 22, and 25.    -   The use of thin foils as illustrated in FIG. 25 allows the        simultaneous manufacture of thin fin structures that enhance the        surface area and maximize heat release.    -   The ability to join multiple sections of a complex heat pipe        while maintaining wick consistency and continuity, allows the        capture of heat from different places, the transfer of such heat        over short or long distances using a larger, more efficient heat        pipe, and the delivery of such heat to multiple places by means        of smaller heat pipes.    -   The control features of an on/off switch in heat pipes that        allows one to interrupt or to maintain the flow of heat at will.    -   The use of special configuration heat pipes, such as pulsating        heat pipes, that permit the vertical or horizontal transfer of        heat over very long distances.    -   The use of different encapsulating materials for the ends and        the middle of heat pipes that optimize heat capture and release,        while minimizing heat losses during heat transfer by means of        connecting materials having low thermal conductivity, or        insulating coatings on the outside of the heat pipes.    -   The possible integration of heat pipes with heat storage systems        that provide for operational flexibility in industrial plants.

-   All of these contribute to superior thermal characteristics.

The ability of capturing, transferring, and releasing heat moreefficiently than heat exchangers, or the so called “economizers” thatrely of thermal fluids, or quenching operations based on water spraysconfers distinct advantages to the heat pipes described in previousparagraphs in multiple industrial applications, such as:

-   -   In water purification and, in particular, in desalination of        seawater, purification of brackish water, purification of        ultra-saline aqueous waste from oil and gas extraction, chemical        or metallurgical processes, pulp and paper industries, and        plastic and rubber operations, to name a few. In effect, the low        temperature differential afforded by heat pipes permits the use        of more effective multiple evaporators in distillation systems,        and the superior heat transfer of heat pipes enhances thermal        performance. Furthermore, water purification configurations can        include multiple designs, such as vertically arranged stacks,        laterally arranged distillation systems, or hybrid        configurations that fall under the category of “distillation        cores.”    -   In chemical and petrochemical processing that require either        effective cooling of exothermic reactions, maintaining of        reaction temperatures within a narrow range, refrigerating of        vessels for synthesis or catalytic reactions at low        temperatures.    -   In power plants, nuclear plants, and similar industries that        require effective cooling, such as by the replacement of cooling        towers and other cooling systems with highly effective heat pipe        driven condenser vessels. Conversely, in using the heat release        features of heat pipes for pre-heating process vessels, or        controlling the temperature of flue gases. And particularly in        the recovery of low-grade heat from flue gases using        aero-dynamically shaped heat pipes that may also be inclined        from orthogonal angles in order to reduce drag.    -   In metallurgical operations that generate heat intermittently,        such as steel and non-ferrous plants, or that require        controlling temperature as in metallurgical digestion processes        such as in the Bayer process.    -   In the efficient transfer and release of large heat energies, as        in enhanced oil recovery, oil and gas fracking operations, gas        hub operations that recover heat from compressors, oil        refineries (e.g., distillation towers, coker operation, and        cooling towers), geothermal energy production, and metallurgical        and chemical operations.    -   In miscellaneous applications, such as food and beverage        processing.    -   And especially in military operations that generate large        amounts of waste heat while requiring potable water obtained        from contaminated sources.

One skilled in the art will appreciate that these methods and devicesare and may be adapted to carry out the objects and obtain the ends andadvantages mentioned, as well as various other advantages and benefits.The methods, procedures, and devices described herein are presentlyrepresentative of preferred embodiments and are exemplary and are notintended as limitations on the scope of the invention. Changes thereinand other uses will occur to those skilled in the art which areencompassed within the spirit of the invention and are defined by thescope of the disclosure. For example, an inner wick can be sprinkledinside the pipe tube and subsequently sintered at the appropriatetemperature, which depends on the sintered material.

All patents and publications are herein incorporated by reference to thesame extent as if each individual publication was specifically andindividually indicated to be incorporated by reference.

The invention illustratively described herein suitably can be practicedin the abs of any element or elements, limitation or limitations whichis/are not specifically disclosed herein. The terms and expressionswhich have been employed are used as terms of description and not oflimitation, and there is no intention that in the use of such terms andexpressions indicates the exclusion of equivalents of the features shownand described or portions thereof. It is recognized that variousmodifications are possible within the scope of the invention disclosed.Thus, it should be understood that although the present invention hasbeen specifically disclosed by preferred embodiments and optionalfeatures, modification and variation of the concepts herein disclosedmay be resorted to by those skilled in the art, and that suchmodifications and variations are considered to be within the scope ofthis invention as defined by the disclosure.

1.-29. (canceled)
 30. A heat management system comprising one or moreheat transfer devices selected from the group consisting of conventionalheat pipes, advanced heat pipes, thermosyphons, heat spreaders,pulsating or loop heat pipes, steam pipes or combinations thereofassembled into an entity providing continuous thermal communicationadapted to capture, transfer, and release heat at temperatures in therange of −40° C. to 1,300° C. at a distance of from 0.1 m to 14 km witha temperature loss from capture to release between 0% and 40% of atemperature at a source of the heat to be transferred, wherein the heatthus transported is from one or more heat sources, and wherein the heattransfer devices capture or provide heat for at least one application.31. A heat management system comprising a plurality of heat transferdevices selected from the group consisting of conventional heat pipes,advanced heat pipes, thermosyphons, heat spreaders, pulsating or loopheat pipes, steam pipes, or combinations thereof assembled into anentity providing continuous thermal communication, adapted to capture,transfer, and release heat at temperatures in the range of −40° C. to1,300° C. at a distances of from 0.1 m to 14 km, with a temperature lossfrom capture to release between 0% and 40% of a temperature at a sourceof the heat to be transferred, wherein the heat thus transferred is fromone or more heat sources, and wherein the heat transfer devices captureor provide heat for at least one application.
 32. The system of claim30, wherein the heat transfer devices have one or more wicks.
 33. Thesystem of claim 30, wherein the heat transfer devices have no wicks. 34.The system of claim 30, wherein the heat transfer devices comprisemultiple sections, the sections being selected from evaporators, heattransfer sections, and condensers, or a combination thereof.
 35. Thesystem of claim 34, wherein the sections comprise a wick characteristicselected from no wicks, full wicks, partial wicks, and any combinationthereof.
 36. The system of claim 30, wherein the at least oneapplication is selected from power plants, geothermal energy production,enhanced oil recovery, gas recompression, water desalination,metallurgical processing, chemical and petrochemical operations andproduction, pulp and paper industries, plastic and rubber operations,refractory industry, glassmaking operations, mining operations, plywoodand oriented strand board manufacturing, fermentation, fertilizerproduction, industrial gas production, military applications, solarenergy production, rubber manufacturing, and oil refineries.
 37. Thesystem of claim 30, wherein the heat transfer devices comprise anencapsulating material manufactured from the group of materialsconsisting of steel, copper and its alloys, titanium and its alloys,aluminum and its alloys, nickel and chromium alloys, wound metal foils,wire screens and scaffolds.
 38. The system of claim 37, wherein theencapsulating material of the heat transfer devices includes a metal,plastic, or ceramic composition that is non-reactive with respect to thevariety of heat sources, non-reactive with respect to a heat transfermedium, and non-reactive with respect to the heat source.
 39. The systemof claim 37, wherein the heat transfer device comprises different metalsand alloys comprising varying thermal conductivities.
 40. The system ofclaim 32, wherein different individual wicked heat transfer devices arejoined such that a joined wick structure exists, having continuitycompatible with capillary action along the length, the continuitypermitting thermal communication of internal working materialsthroughout the length, and wherein the internal working materials areselected from the group consisting of fluids, solids that sublimate,materials having multiple chemical hydration levels, and any combinationthereof.
 41. The system of claim 32, wherein the wick structurecomprises multiple layers having different porosities.
 42. The system ofclaim 32, wherein the wick structure comprises an internal wickstructure comprising an axial wick.
 43. The system of claim 32, whereinthe wick structure comprises at least one material selected from thegroup consisting of sintered metals, metal screens, grooves, oxides,borates, solids that sublimate, materials with different chemicalhydration levels, nano-particles, nanopores, nanotubes, and anycombination thereof.
 44. The system of claim 14, wherein differentmaterials are used at different positions along the length, and whereinthe materials are selected to optimize heat capture and release, whileminimizing heat loss.
 45. The system of claim 43, wherein the wick isformed by spraying, painting, baking, PVD, CVD, or pyrolysis of organiccompounds.
 46. The system of claim 32, wherein the wick is formed bythermally decomposing a slurry of metal particles in a liquid metalprecursor.
 47. The system of claim 30, wherein the encapsulating tubecomprises a wound strip of thin foil.
 48. The system of claim 47,wherein the wound strip structure is pre-coated with wick materialbefore being formed into tubular assemblies around metal scaffoldscomprising mesh screens.
 49. The system of claim 47, wherein gaps in thewound tube are sealed by a separate wound strip.
 50. The system of claim49, wherein the amount of working material is in excess of what isneeded to saturate the internal wick structure.
 51. The system of claim30, wherein the working material in the heat transfer devices has phasechange temperature in the range of −40° C. and 1,300° C.
 52. The systemof claim 30, wherein the heat transfer device comprises a valveproximate to one end in order to control and maintain partial vacuum.53. The system of claim 30, wherein vertical heat transfer devices of upto 14 km in length are installed to prevent the physical degradation orbreakage of the heat transfer devices, wherein the weight of the heattransfer device is neutralized by at least one buoyant balloon, at leastone helicopter, or a combination thereof.
 54. The system of claim 30,where the heat transfer devices are installed using at least oneinstallation aid selected from a crane, a helicopter, a balloon, awheel, an oil rig, and a tower, or any combination thereof.
 55. Thesystem of claim 30, wherein heat transfer devices of 3-7 Km in lengthare installed without physical degradation or breakage of such heattransfer devices, and wherein the heat transfer device is wound around awheel of 100-500 feet in diameter that minimizes the curvature of theheat transfer device.
 56. The system of claim 30, where the heattransfer devices are insulated.
 57. The system of claim 30, whereinpulsating heat pipes are made by encapsulating a thin metal or alloylayer in a strong metal screen to resist pressure pulses.
 58. A methodof heat capture, transfer and release, using the system of claim
 30. 59.A method for manufacturing the system of claim 30, comprising the stepsof: selecting the type of heat transfer device from the group consistingof conventional heat pipes, advanced heat pipes, thermosyphons, spreaderheatpipes, loop heat pipes, pulsating heat pipes, steam pipes and anycombination thereof; selecting a method of joining heat transfer deviceelements from at least one method the group consisting of soldering,brazing, welding, threading, foil winding, mechanical fittings,encapsulating thermal fluids, and any combination thereof; selecting atype of wick structure from the group consisting of sintered metal,axial wick, metal screens, grooves, any combination thereof, and no wickmaterial; selecting the internal working material from the groupconsisting of aqueous solutions, eutectic salt mixtures, organic thermalfluids, and high-temperature metals and alloys that liquefy attemperatures in the range of −40° C. to 1,300° C., solids thatsublimate, and materials with different chemical hydration levels;applying the joining method, wick structure, and working fluid thusselected; and sealing the heat transfer device under vacuum.